PyFilesystem can open a filesystem via an FS URL, which is similar to a URL you might enter in to a browser. FS URLs are useful if you want to specify a filesystem dynamically, such as in a conf file or from the command line.


FS URLs are formatted in the following way:


The components are as follows:

  • <protocol> Identifies the type of filesystem to create. e.g. osfs, ftp.
  • <username> Optional username.
  • <password> Optional password.
  • <resource> A resource, which may be a domain, path, or both.

Here are a few examples:


If <type> is not specified then it is assumed to be an OSFS, i.e. the following FS URLs are equivalent:



The username and passwords fields may not contain a colon (:) or an @ symbol. If you need these symbols they may be percent encoded.

URL Parameters

FS URLs may also be appended with a ? symbol followed by a url-encoded query string. For example:


The query string would be decoded as {"key1": "value1", "key2": ""}.

Query strings are used to provide additional filesystem-specific information used when opening. See the filesystem documentation for information on what query string parameters are supported.

Opening FS URLS

To open a filesysem with a FS URL, you can use open_fs(), which may be imported and used as follows:

from fs import open_fs
projects_fs = open_fs('osfs://~/projects')

Manually registering Openers

The fs.opener registry uses an entry point to install external openers (see Creating an extension), and it does so once, when you import fs for the first time. In some rare cases where entry points are not available (for instance, when running an embedded interpreter) or when extensions are installed after the interpreter has started (for instance in a notebook, see PyFilesystem2#485).

However, a new opener can be installed manually at any time with the fs.opener.registry.install method. For instance, here’s how the opener for the s3fs extension can be added to the registry:

import fs.opener
from fs_s3fs.opener import S3FSOpener

# fs.open_fs("s3fs://...") should now work